Automatically-controlled vapor-converter substation



July 17, 1928.

wQv. LOVELL AUTOMATICALLY CONTROLLED VAPOR OONVERTER S UBSTATION Original Filed 001;. 5, 1917 16.6 26 Nu .l mum kmt @500 h mm 0% ll. IlE.

WITNESSES:

INVENTOR William V Lovell.

ATTORNEY Reissued July 17, 1928.

UNITED STATES,

Re. 17,041 PATENT OFFICE.

WILL IAM V. LOVELL, OF NEW YORK, N. Y., ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

AUTOMATICALLY-CONTROLIED VAPOR-CONVERTER SUBS'IATION.

Original No. 1,388,147, dated August 30, 1921, Serial No. 194,457, filed October 3, 1917. Application for reissue fled April 13,1923. Serial No. 631,922.

My invention rclates'to means for automatically controlling the operation of a lurality of convertin devices when nst-a led in substations emp oyed in connection with electric power-distribution systems.

An automatically-controlledsubstation may be defined as one in which theseveral operations of starting and connecting the converting apparatus to the line, whenever there is a demand for power, and finally shutting down and disconnecting the converting apparatus, afterthe demand for power has ceased, are all performed in thelr proper sequence without the assistance of an operator, either in the substation or in adjacent stations. The automatically-controlled substation has no direct connection to the main generating station other than through the power-Suppl circuits and is, therefore, essentially di erent from a remotely-controlled substation which requ res a separate feeder to each piece of converting apparatus and in which the operations of both stopping and starting the apparatus are performed by an attendant in the station from which the power is supplied.

'In Patent No. 1,358,713, issued November 16, 1920, to Edward. P. Dillon, and assigned to the Westinghouse Electric & Manufacturing Company, is shown and described an automatically controlled vapor-converter substation in which the operatlons of starting and shutting down of a vapor converter are automatically controlled in accordance with changes in the condition of the electric circuits to which the converter is connected. The above-mentioned patent also describes an arrangement by means of which the converter is automatically shut down upon the occurrence of certain unfavorable conditions in its cooling system.

proper operating condition, as regards the absolute gas pressure therein, will he placed in service, the operation of my system being entirely selective with respect to both the number and operating condition of the converters that are placed in service at any time.

The single figure of the accompanying drawing is a diagrammatic view of the apparatus and circuit connections employed in an automatically controlled substationand arranged in accordance with my invention.

Mainsl are connected to a suitable alternating-current source, such as a single-phase alternator 2, and the primary windings 3 of a plurality of supply transformers 4 are connected to the mains 1 through electricaloperated switches 5. The terminals of the secondary winding 6 of the transformers are respectively connected to the anodes 7 of a plurality of converters 8, and intermediate points 9 of the secondarywindings 6 are respectively connected to one main 10 of a direct-current receiving circuit, through the switches 5. The mercury cathodes 11 of -a lead 61, throiigh the relays 16, 17 and 18,

respectively. he relay 16 comprises an actuating c011 19, the terminals of which are connected to the control conductors 14 and 15 through the relatively movable contact members 20 and 21 of an indicating instru-' ment 22 of the voltmeter t pe. The instrument 22 comprises a sensitive voltage coil 23, the terminals of which are connected to theterminals of a coil 24, preferably composed of tungsten or similar metal that is located within the casing of the converter 8. I

The instrument 22, together with the filament 24, constitutes what. is known as a resistance-type vacuum gage, fully described in S. Patent 1,274,635, issued to the Westmghouse Electric & Manufacturing Com an on Aug. 6, 1918, on an application 1e by William Tschudy. In brief, the

action is as follows. Constant current is passed through the filament and, as the absolute pressure of the surrounding medium ischanged, the amount of heat removed b conviction is changed, resulting in the a teration of the filament resistance, and, accordingly, of the IR drop thereacross. Rectifying devices of the vapor-arc type demand a certain absolute ressure for maxlmum efficiency, and it is t e purpose of this vacuum gage to insure that a rectifier is not connected to the line if materially off in its absolute pressure. The coil 24 is connected in series with a source 25 of constant current through leads 62 and 63 and, as the current traversing the coil 24 varies in accordance with the pressure within the casing of the converter, the voltage drop across the coil 24 Wlll also vary in accordance with the pressure within the casing. It is obvious, therefore, that the voltage impressed upon the coil 23 will vary in accordance with changes in the pressure within the casing of the converter. The movable contact member 21 of the device 22 is pivotally mounted and is adapted to be 21. Thus, the coil 19 of the relay 16 will be energized only when the pressure within the casing of'the converteris within certain limits. For instance, if the converter is of the vacuum type, the instrument 22 will be calibrated for degrees of vacuum but it will be readily understood that, if a gas other than air be employed within the casing of the converter, it may 'be found desirable to use a pressure of several atmospheres, in which case, the instrument 22 will be calibrated accordingly. From the foregoing, it is apparent that the closing coil 13 of the switch 5 will be energized and the converter 8 brought into service only within the optimum range of the'absolute gas pressure within the casing of the converter.

The relay 17 is provided with an actuating coil 28 that is connected across the controlthe switch 5, the said circuit being completed by' the upper bridging member 36 only when .18 are con-' nected in the circuit of an opening coil of the voltage across the direct-current mains 1O exceeds a predetermined value. The relay 18 is so designed that its bridging members 33 and 36 are out of engagement with the respective pairs of stationary contact members-32 and 34 as long as the voltage across the direct-current mains 10 is within certain limits. The switch 5 is further pro vided with an overload tripping coil 37 that is adapted to be energized from the secondary winding 38 of a series transformer located in one of the leads to the primary winding 3 of the transformer 4, in response to substantially short-eircuit conditions.

The relay 16 is further provided with lowerstationary contact members 39 one of which is connected in the circuit of the closing coil 13 at a point 40 intermediate the a live-line relay 42. The actuating coils 43 and 43' of the relays 42 and 42 are adapted tobe energized from shunts 44 and 44, respectively, located'in leads to one of the direct-current mains 10. 7 Consequently, the bridging members 45 and 45 are held out of engagement with the contact members 41 and 41' as long as the converter is in service.

Each converter 8 is further provided with overload time-limitrelays 46 and 46 respectively, the stationary contact members 47 and 47 of which are connected between the control main 15 and the lead connecting the contact members 39 to the contact members 41 of the relay 42 of the next adjacent converter. The actuating coil 48 of the relay 46 is adapted to be energiz'ed from a shunt 49 located in one of the direct-current leads of the converter. V

A low-line-voltage relay 5O comprises stationary contact members 51 that are connected between the control main 15 and the point 40 in the circuit of theclosing coil 13 of the left hand converter 8. The voltage coil 52 of the relay is connected acrossthe. directcurrent mains 10, and-the bridging member 53 is held out 'of'enga'gement with the contact members 51 as long as the voltage across switch 5 through the contact members 41 of the direct-current mains 10 exceeds-a prede termined value.

Each converter is provided with starting or keep-alive device that comprises an electrode 55 that is suspended from a cap 56 by a flexible conductor 57. The cap= 56 is formed of conducting material and is suitably insulated from the casing 8 of the converter. The cap 56 is surrounded by a solenoid 58, one terminal of w'hichis connected to the cap 56 and the other terminal of which is connected to .the control conductor 14 through the switch 5. The electrode 55 is provided with a core 59 that is adapted to be drawn up within the cap 56 when the solenoid 58 is energized. The electrode 55 is of suflicient length to extend below the surface of the mercury in the casing when the solenoid 58 is de-energized and is adapted to be withdrawn from the mercury when the coil is energized, thereby drawing an are between the end of the electrode and the surface of the mercury.

Having described the various parts entering into my invention, the operation thereof, under various operating conditions, will now be discussed. For the first condition, it will be assumed that none of the converters 8 are connected to the alternating and direct-current supply and receiving circuits. vIf the volta e across the direct-current mains 1O falls below a predetermined value, the contact members 51 of the relay 50 will be connected. As the left-hand converter, which will hereinafter be designated as #1, is in its proper operating condition,-as indicated by the lnstrument 22, the circuit of the closing coil 13 is completed and the switch 5 will close, thereby energizing the solenoid 58 of the keep-alive? device and putting 0011-. In case the pres sure within the converter #1 is not within verter #1 in operation.

the optimum range, the upper contact members of the relay 16 will be open, thereby rendering itimpossible for the switch 5 to be closed. In this event, the lower contact members of the relay 16 are closed and the circuit-of the closing-coil 13 of converter #2, or of the next adjacent, converter that is in proper operating condition, will be completed. 7

For the next operating condition, letit be assumedrthat converter"#1 is operating alone and that converter #2 is in an operating condition, as indicated. If the voltage across the direct-current mains 1O falls below a predetermined value, because of an excessive IR drop due to heavy load current, the following sequence of action will occur in the con trol system of converter #2. The lower bridging member 33 of the relay 18' will drop and complete the circuit between the contact members 32'. As relays 16 and 177 .are both closed, the circuit of the closing coil 13' is completed and the switch 5' will be closed. Converters #1 and #2 will then be in operation. Assuming that the demand 6 for direct-current energy which caused the drop in voltage, as described above, has ceased, the voltage across the direct-current mains will then rise and, if it exceeds a predetermined value, the upper bridging member 36' of the relay 18 will move upwardly and complete the circuit of the opening coil 35', thereby removing converter #2 from the line. The actuating coils 31 and 31 of the relays 18. and 18" are so calibrated that the converter #2 will drop out before converter #1; converter #3 before #2, and so on.

For the next operating condition, let it again be assumed that converter #1 is operating and that it is overloaded although the voltage across the direct-current mains 10 is within normal limits. The-relay 46 will then close and connect the point 40 in the closing-coil circuit of converter #2 to the control main 15. I If converter #2 is in the proper operating condition, the upper contact terminals of the relay 16 will be closed, and converter #2 will be immediately connected to the line. If, however, the gas pressure within converter #2 is above or elow the optimum range, the upper contacts ofthe relay 16 will be open and it will be impossible for the switch 5 to be closed. In this event, the lower contact members of the relay 16 are closed and the next adjacent converter that'is in proper operating condition will be connected to the line, as previously described.

While various other operating conditions too numerous to be mentioned herein might .be described, it is obvious that the demand for direct-current energy, in a vapor converter system embodying my invention, will always be met by the selective operation of only thoseconverters which are in proper operating condition. Furthermore, it will be impossible to overload a converter unit so long as there are any units remaining in reserve that are in proper operating condition. While I have shown my invention in its simplest and preferred form and as embodying specific forms of control devices, it is .not solimited but is susceptible of various minor changes and modifications within the scope of the appended claims. I claim as my invention: 1. The combination with an alternating current source and a direct-current consuming circuit, of a plurality of vapor converters and means for selectively connecting tions in said circuit and upon the internal pressures of the converters for selectively connecting the converters to said circuit.

. within the converter.

4. The combination with an alternatingcurrent source and a direct-current consuming circuit, of a plurality of vapor converters adapted to be connected therebetween, and automatic means for insuring the disconnection of any converters which have faults of operation dependent upon pressure "current source and a direct-current consuming circuit,- of a lurality of vapor converters, one of which is connected to said circuit. automatic means for disconnecting said converter from said circuit and means dependent upon the actuation of said firstnamed means for selectively connecting one of the remaining converters to said circuit having the optimum operating gas pressure therewithin.

7. In an electrical power system, the com bination with an alternating-current circuit, a direct-current circuit and a plurality of converters for translating energy therebetween, of means for connecting the converters between the two'circuits in a predetermined sequence in accordance with the power demand on one of the circuits and means responsive to a predetermined condition of the converters for varying said sequence.

8. In an electrical power system, the combination with an alternatin current circuit, a direct-current circuit an a plurality of converters for translating energy therebetween, of means for connecting the convcrters between the two circuits and means comprising an individual load-responsive relay associated with each converter and means responsive to the proper operating conditions of the converters for controlling the connection of another converter to thesystem when the associated converter is loaded to a predetermined degree.

' ;9. In an electrical power system, the combination with an alternating-current circuit, a direct-current circuit and a plurality of converters for translating energy therebetween, of means for connecting the con-.

verters b-atWQQ-l'l the two circuits, means whereby the connecting means of the respectlve converters may be arranged to connect the converters to the system in a pre-determined sequence and means responsiveto a redetermined 'conditlon of the converters or varying said sequence.

10.; In an electrical power system, the combination with an alternating-current circuit, a direct-current circuit and a plurality of converters for translating energy therebetween, of means for connecting the converters between the two circuits and means responsive to an abnormal condition in one converter, by reason of which it is desired to preclude the operation thereof, for controlling the operation of the connecting means of another converter.

11. In an electrical power system, the combination with an altcniating-current circuit, a dircct current circuit and a plurality of converters for translating energy therebetween, of means for connecting the conventers between the two circuits, means whereby the connecting means are caused to operate to connect the respective converters to the system in a predetermined sequence according to the energy demand upon the'system and means responsive to an abnormal condition in any converter or the associated connecting means, by reason of which it is desired to preclude the operation of such converter or connecting means, for controlling the connecting means ofanother converter.

12. In an electrical system, the combination with a circuit to which a plurality of llNl 13. In an electricsystem, the combination with an electric circuit and a plurality of electrical translating devices, of means responsive to the power demand on said circuit for automatically connecting the devices into the circuit in predetermined sequence, and means responsive to abnormal conditions in said devices for preventing the connection thereof into said circuit.

14. In an electrical power system, the combination with an alternating-current circuit, a direct-current circuit and a plurality of converters for translating energy therebetween, means dependent upon the proper operative condition of one of said converters for efiectin the electrical connection thereof to said clrcuits, means responsive to load conditions in said converter for connecting additional converters to said circuits, and means responsive to predetermined conditions in said additional converters for preventing the electrical connection thereof to said circuits.

15; The combination with an electric circuit and a plurality of "electrical devices to be connected thereto, of means for automaticaily connecting said devices in saidcircuit in predetermined sequence, and means asso-' 5 mated with each of said devices res onslve to predetermined conditions therein or preventing the connection of the device in said circuit.

In testimony whereof, I have hereunto subscribed m 1923.

y name this 7th day of March, 10

' WILLIAM V. LOVELL. 

